Hygiene articles like pantiliners, sanitary napkins, tampons, diapers and so on are used to absorb/retain bodily discharge. A problem associated with bodily discharge (vaginal discharge including vaginal fluids, and/or menstruation, urinal discharge, faeces or perspiration) is the generation of undesirable odors within such hygiene articles that have the tendency to escape out of the articles.
Many products and articles are available which aim to prevent the occurrence of malodours and/or to avoid and minimise the detection of malodours typically associated with bodily discharge.
Various odour control materials have been disclosed in the art to combat some of the unpleasant odours associated with body fluid discharges. Indeed solutions have been provided that use different technical approaches like masking, i.e., covering the odour with a perfume, or absorbing the odour already present in the bodily fluids and those generated after degradation, or preventing the formation of the odour.
Most of the focus in the prior art is found on the odour absorption technology. Examples of these types of compounds include activated carbons, clays, zeolites, silicates, absorbing gelling materials, starches, cyclodextrine, ion exchange resins and various mixture thereof as for example described in EP-A-348 978, EP-A-510 619, WO 91/12029, WO 91/11977, WO 89/02698, and/or WO 91/12030. All of these types of odour control agents are believed to control odour by mechanisms whereby the malodorous compounds and their precursors are physically absorbed by the agents and thereby hinder the exit of the odour from articles like absorbent articles. However, such mechanisms are not completely effective as the formation of the odour itself is not prevented and thus odour detection is not completely avoided. Also the drawback with these odour-absorbing agents is that, the bacteria are still able to grow, and the use of bacteria inhibiting agents, which are often selective, can create risks, for instance, in the form of allergenic properties or negative ecological consequences when handling waste. Furthermore, the use of bacteria inhibiting agents involves the risk that resistant strains will occur.
It is known within the medicine and foodstuff technologies to use bioconservation with the aid of bacterial antagonism as a conserving method, and to inoculate special bacteria strains to favourize bacteria populations that are beneficial to the stomach and intestines, for health-promoting purposes. Examples in this respect are conventional yogurt and soured milk, and also novel bioactive foodstuffs. This methodology also includes the use of bacteria such as so-called probiotic bacteria as a substitute for antibiotic bacteria.
International Patent Application WO 92/13577 describes a tampon or sanitary napkin that has been impregnated with a culture of lactic-acid producing bacteria, preferably of the genus Pediococcus, isolated from healthy individuals. The tampon or sanitary napkin is intended for the prophylactic treatment of urogenital infections. WO 97/02846 discloses an absorbent article with antagonistic microorganisms selected from the family Lactobacillaceae, preferably from the genera Lactobacillus or Lactococcus. 
However, the problem encountered with such articles of the prior art is the stability of the articles both during storage and use. None of these prior art documents discloses anything about providing articles, especially disposable absorbent articles, which exhibit antagonistic properties against undesirable pathogens, which articles can be stored for a long time and still contain a sufficient amount of active and transferable bacteria. It is absolutely necessary that consumer products such as disposable absorbent articles can be stored for a long time and under non-ideal conditions without risking that the quality of the articles is impaired. Consequently, there is a need for articles delivering antagonistic properties against pathogens, which articles are specially adopted for long-time storage under unfavorable conditions and for maintaining their antagonistic properties against pathogens in use.
An attempt has been made in this direction in WO 99/17813 which discloses absorbent articles with a suspension of lactic acid bacteria from the genera Lactobacillus, Lactococcus or Pediococcus, the article being dried after application of the suspension, to a moisture content of less than 10% calculated as percentage of weight of the absorbent core in the article. However such articles do not fully meet the problems mentioned herein before. Also the production of such articles requires an extra drying step which impairs on the manufacturing requirements of speed and cost.
The object of the present invention is to provide an article for external application to a human or animal, without permitting pathogenic microorganisms to grow or to become active to an extent such as to promote undesirable odours.
More particularly, it is an object of the present invention to provide disposable absorbent articles which deliver a broader spectrum of odour control mainly by preventing the formation of malodours while not compromising on the overall protection delivered by such articles or even improving protection (e.g., reducing wet through and/or reducing re-wetting).
It is a further object of the present invention to provide such articles which are stable over prolonged time of storage without risking that the quality of the articles is impaired.
Yet, it is a further object of the present invention to provide articles which deliver a sustained antagonistic effect against undesirable strains of microorganisms. More particularly it is an object of the present invention to provide articles, especially disposable absorbent articles, which deliver a sustained odour control over prolonged use time of the articles, i.e., a long lasting odour control by preventing the formation of odour over prolonged wearing time of the articles.
Finally, it is an object of the present invention to provide articles, especially disposable absorbent articles, having the benefits mentioned herein before while meeting the requirements of ease of manufacturing, time effectiveness and cost effectiveness.
These objects have been achieved in accordance with the present invention by providing a disposable article comprising an absorbent core containing spores which are able to germinate under favorable conditions (typically in use conditions, e.g., when the article is applied to the external surface of a human or animal) in microorganisms (i.e., the corresponding living form of the spores) which exhibit antagonistic properties against undesirable strains of microorganisms, typically present or arisen in the article upon contact with bodily fluids.
The living form of the spores have an activity such as to restrain the growth of undesirable strains of microorganisms or establishing of new undesirable species of microorganisms. Even some killing of microorganisms of undesirable species may occur. Indeed, the living form of the spores used in the present invention have the ability to inhibit undesirable strains of micro-organisms by competing for substrate. The antagonistic properties of the living form of the spores used herein is further partly denoted their ability of producing different so called antimetabolites, such as lactic acid, lactoperoxidases, bacteriocins and carbon dioxides.
More particularly, it has been surprisingly discovered that the use, in the absorbent core of an disposable absorbent article, of spores of micro-organisms which exhibit antagonistic properties against undesirable pathogens (preferably B coagulans spores also called herein after L. sporogenes), provides an effective odour controlling article which can be stored for long time periods before its actual use, without risking that the odour control ability of the article in use is impaired. The use of these spores able storage stability upon prolonged periods of time up to the time the article is used, i.e., is applied on the external surface of a human or animal body where it typically comes into contact with bodily fluids, and undergoes environmental changes that will create favourable environmental condition for the germination of the spores. In use conditions, for example when a disposable article is applied onto the skin or in the urogenital zone, the body temperature, the micro-environmental humidity and the availability of nutriments like menses, vaginal discharge, urine, perspiration and the like, will allow transformation/germination of the spores (dormant form) in the microorganisms (living form).
Advantageously, the spore-containing articles according to the present invention retain their whole antagonistic properties against pathogens like the odour control capacity up to the time their are used. Thus the present invention also allows to provide articles with effective antagonistic properties, e.g., odour controlling ability, while using reduced total amount of active material (typically odour control material). Indeed a reduced total amount of spores according to the present invention is needed to obtain a given odour control activity for a given disposable article as compared to the total amount of non-spore forming antagonistic micro-organisms like Lactobacillus, Pediococcus, or Lactococcus that would be needed to get the same activity.
In one aspect of the present invention the disposable absorbent article will comprise within its absorbent core spore-forming microorganisms (living form of the microorganisms) exhibiting antagonistic properties against undesirable strains of microorganisms as an alternative or in mixture with the spores described herein.
Advantageously the spore-forming micro-organisms able to exhibit antagonistic properties against pathogens used herein, preferably the species B. coagulans, have the ability to create very quickly an environment that is not suitable for the growth of pathogens. This is due to the rapid growth, high yield and reproducibility of such micro-organisms in comparison to non-spore forming bacteria like Lactobacillus acidophilus. The spore forming micro-organisms used herein are able to survive longer and reproduce themselves in comparison to non spore-forming micro-organisms. In other words, by the formation of spores these micro-organisms can germinate and re-germinate in time sequence in line with the bodily fluid discharge (growth media) into an absorbent article, thereby ensuring long-lasting antagonistic properties against pathogens.
Without to be bound by theory, it is speculated herein that in the event where the bodily fluid discharge is reduced and hence less substrate is available for the micro-organisms, the micro-organisms used herein have the ability to be transformed in a dormant form, i.e., spore form, which will be activated again upon availability of further substrate, typically upon further bodily fluid discharge. Thus also when providing the disposable absorbent articles with the living form, i.e. the spore forming micro-organisms, effective antagonistic properties, e.g., odour controlling ability, while using reduced total amount of active material (typically odour control material).
It is an advantage of the present invention to provide a disposable absorbent article which can be worn for a relatively long period of time without microorganisms being allowed to grow to an extent in which undesirable odours are generated. Advantageously the genetic identity, the lactic acid producing ability, the viability as well as the valuable antagonistic properties against pathogens are maintained even upon prolonged periods of use, typically during the whole wearing time of the article, e.g., up to 1 hour to 10 hours as need arises.
A further advantage associated with the disposable absorbent articles of the present invention (e.g., pantiliners or pads) comprising within the absorbent core a spore-forming antagonistic microorganism and/or the spores thereof (dormant form of the micro-organisms), is a better protection as well as better feeling and more acceptable cleanness level in use. Indeed, it has further been found that the spore forming microorganism and/or spores described herein, allow gelification of the bodily fluid discharge upon contact therewith, thereby facilitating fluid control into the article. Indeed the presence of the spore forming microorganisms and/or spores in the absorbent core of the absorbent article by changing the physical properties of the bodily fluid discharge enhances the fluid control properties of the article. Such gelification will have the benefits of retaining the bodily fluid within the absorbent core thereby reducing the rewetting of the topsheet and/or the soiling through as might otherwise result from squeezing the article for example as a consequence of legs movement of a person wearing the article.
Whereas the present invention is preferably directed to disposable articles like pantiliners, feminine napkins, incontinent pads, diapers, tampons, interlabial pads, perspiration pads, surgical pads, breast pads, human or animal waste management devices and the like, other articles may include the spores as described herein and/or micro-organisms too for the purpose of malodours control. Indeed, other applications include other articles designed to be worn in contact with the external surface of a human or an animal such as clothing, bandages, thermal pads, acne pads, cold pads, compresses, surgical pads/dressings and the like, body cleansing articles like impregnated wipes (e.g. baby wipes, wipes for feminine intimate hygiene), articles for absorbing perspiration such as shoe insoles, and articles for animals like litters and the like.